I also ported the constant_propagation.sil tests over for ownership and updated
a few parts of the cast optimizer so that those tests pass with and without
ownership. I purposely only updated the parts of the cast optimizer that crashed
with ownership in the relevant test so that I can add new sil code coverage for
those uncovered code paths.
I am going to add the code in a bit that does the notifications. I tried to pass
down the builder instead of the pass manager. I also tried not to change the
formatting.
rdar://42301529
Correct format:
```
//===--- Name of file - Description ----------------------------*- Lang -*-===//
```
Notes:
* Comment line should be exactly 80 chars.
* Padding: Pad with dashes after "Description" to reach 80 chars.
* "Name of file", "Description" and "Lang" are all optional.
* In case of missing "Lang": drop the "-*-" markers.
* In case of missing space: drop one, two or three dashes before "Name of file".
(Headers first)
It has been generally agreed that we need to do this reorg, and now
seems like the perfect time. Some major pass reorganization is in the
works.
This does not have to be the final word on the matter. The consensus
among those working on the code is that it's much better than what we
had and a better starting point for future bike shedding.
Note that the previous organization was designed to allow separate
analysis and optimization libraries. It turns out this is an
artificial distinction and not an important goal.
